[Histological grading of soft tissue sarcomas: stratification of G2-sarcomas in low- or high-grade malignant tumors]

Abstract

Histological grading according to one of the proven systems, e.g. that of the FFCCS, leads to the definition of different prognostic risk groups. Prerequisite is a precise typing of the tumors, if necessary by immunohistochemical and molecular-pathological methods. The therapeutic decision is dependent on the presence either of a low- or high-grade malignant tumor: With low-grade sarcomas surgery has priority, with high grade tumors usually chemo- and/or radiotherapy are indicated. With the latter, also better therapeutic response is reported. Therefore, conversion of a 3-grade into a 2-grade system has to be carried out by including the tumor localization as prognostic parameter. Thereby, the large group of G2-sarcomas with intermediate malignancy can be stratified. Superficial G2-sarcomas are considered to be low grade and deep G2-sarcomas high grade malignant. Immunohistochemical staining of tumor cell nuclei with Ki67/MIB1 allows a more standardized and precise grading. The ultimate aim, not to define risk groups, but to predict the prognosis for individual patients, possibly could be reached someday by molecular diagnostic methods.